The theme of our Superfund Basic Research Program continues the achievements of the previous grant which is to develop a risk assessment process for metal and organic contaminants through toxicologic and hydrogeologic studies and through development of innovative remediation technologies. Our application Southwestern hazardous through development of innovative remediation technologies. Our application emphasizes Southwestern hazardous waste issue due to the unique nature of our environment. However, our studies are not limited to the Southwest since the main toxicants being examined, arsenic and chlorinated hydrocarbons, are not unique to the Southwest and our results can be applied to other hazardous waste sites. Our Program consists of 10 research projects-four (4) biomedical projects and six (6) environmental sciences projects. These are supported by 5 Cores that: administer the Program, provide research services promote outreach efforts, and support graduate student training. Our Program culminates in a Community Based Prevention/Intervention Research Project, which addresses an immediate and important environmental health problem and draws on the expertise of our Program, governmental agencies, and the community at risk to handle this environmental issue. The goal of the Biomedical research projects is to determine the fate and processing of arsenic in the body and the effects of low level arsenic exposure on target tissues-skin, kidney, and developing tissues. A continuing goal is to determine the mechanism of trichloroethylene (TCE)-induced effects on the developing tissues. A continuing goal is to determine the mechanism of trichloroethylene (TCE)-induce defects on the developing heart. One component of our studies in environmental sciences is to develop better hydrogeological models of mine wastes and develop approaches for treating this waste. A group of our environmental research projects will develop better methods to improve the removal of complex mixtures from the soils and underground waters of our Southwestern environment and use improved biological techniques (e.g. biosurfactants and gene-augmented microbes) to degrade the hazardous wastes. Finally, our chemists and bioengineers and bioengineers will develop improved, innovative technologies (both chemical and physical) for the treatment and degradation of halogenated organics . Our Program is an integrated effort to address the hazardous waste issues of our region, translate the results to our partners (government, industry, and the community), and fulfill the mandates of the national SBRP Program.